Strut mount

ABSTRACT

The present invention provides a strut mount bolted to a curved outer cylinder attachment plate ( 6 ) without enlarging abolt hole, by inserting a cylindrical portion ( 13 ) of a caulking nut ( 5 ) into a nut attachment hole ( 11 ) of an attachment piece ( 10 ) of an outer cylinder ( 2 ) and pressurizing and diminishing in diameter the circumference of the nut attachment hole ( 11 ) to caulk and stick the nut attachment hole ( 11 ) and the caulking nut ( 5 ).

FIELD OF THE INVENTION

This invention relates to a strut mount disposed at an attachmentportion of a buffer to a vehicle.

DESCRIPTION OF THE RELATED ART

In general, in a suspension system of an automobile, etc., a so-calledstrut mount is disposed at an attachment portion of a buffer to avehicle body, in order to control vibration, etc. propagated from wheelsto the vehicle body.

FIG. 6 shows an example of the strut mount. The strut mount comprises aninner cylinder 101 in which a piston rod of the buffer is fixed, anouter cylinder 102 attached to the vehicle body, and a rubber elastomer103 interposed between the inner and outer cylinders to dampen inputvibration, and a bolt 106 inserted into a bolt hole 105 thereof frombelow is press fitted and secured to an attachment piece 104 of theouter cylinder 102. With the bolt 106 lifted up so as to insert into abolt hole 108 of the vehicle body's outer cylinder attachment plate 107from below and a nut tightened from above the outer cylinder attachmentplate 107, the strut mount will be attached to the vehicle body only byattachment working from above.

In order to raise rigidity and improve running properties, the strutmount shown in FIG. 6 is constructed so that the attachment piece 104 ofthe outer cylinder 102 and the outer cylinder attachment plate 107 ofthe vehicle body are curved in the form of a sphere, and that each bolt106 press fitted and secured to the attachment piece 104 is orientedtoward the inclined direction, respectively, against the direction ofmovement (perpendicular) when the strut mount is lifted up. For thatpurpose, the bolt hole 108 on the outer cylinder attachment plate 107 ismade larger so that the bolt 106 oriented toward the inclined directioncan be inserted.

However, when the bolt hole is large, it is apprehended that there occurproblems related to bolt tightening such as looseness. Therefore, ameans of inserting the bolt, without making the bolt hole larger, andtightening the bolt only by operations from above is pursued.

DISCLOSURE OF THE INVENTION

The present invention has been made in view of the subjects describedabove, and it is an object of the invention to provide a strut mountintended to insert a bolt, without making the bolt larger, and tightenan attachment piece of an outer cylinder at the underside of a vehiclebody's outer cylinder attachment plate, with a bolt, only by operationsfrom above, by providing a nut at the underside of the outer cylinderattachment piece and screwing the bolt into the nut from upside theouter cylinder attachment plate of a vehicle body.

When providing the nut for the attachment piece of the outer cylinder, atechnique that a small hole is drilled at the prescribed position on theattachment piece of the outer cylinder, a burr is formed (burringworking) downwardly around the circumferential edge of the hole as acylindrical portion, and an inner circumferential surface of thecylindrical portion is tapped and cut as screw threads to serve as anut, also comes to mind. However, such technique makes its workingdifficult and complicated. Furthermore, in order to elongate the nut ofa given diameter and cut the required number of screw threads, it isnecessary to thicken the outer cylinder, with the result that the weightof the components grows heavier.

Otherwise, as for the method of welding a nut on the underside of theattachment piece of the outer cylinder, in order to avoid deteriorationof rubber elastomer due to welding heat, it is necessary to weld the nutbefore working the strut mount or to escape welding heat by maskingaround the nut of the attachment piece, whereby making the strut mountworking difficult and complicated.

Accordingly, the present invention adopts a nut securing means of makingthe thickness of the outer cylinder thinner to lightweight thecomponents, without causing difficult and complicated working, andcapable of maintaining the durability of rubber elastomer, by caulkingand securing the nut on the underside of the attachment piece of theouter cylinder.

When caulking and securing the nut to the attachment piece of the outercylinder, either upsetting on the nut side or diminishing in diameterthe nut attachment hole of the outer cylinder can be adopted.

In case of upsetting on the nut side, the nut attachment hole is drilledon the attachment piece of the outer cylinder, on the other hand, acylindrical portion is provided continuously from the nut portion forthe caulking nut: the cylindrical portion is inserted into the nutattachment hole from the underside of the attachment piece of the outercylinder; after that, when the cylindrical portion is upset and caulkedand secured to the nut attachment hole, an outer circumferential surfaceof the cylindrical portion is stuck fast to an inner circumferentialsurface of the nut attachment hole, thus sticking the nut on theunderside of the attachment piece of the outer cylinder.

In case where the nut attachment hole is diminished in diameter, withthe cylindrical portion of the caulking nut inserted into the nutattachment hole from the underside, by pressurizing the circumference ofthe nut attachment hole from the direction square to the plate surfaceof the attachment piece of the outer cylinder, the inner circumferentialsurface of the nut attachment hole is stuck fast to the outercircumferential surface of the cylindrical portion to caulk and stickthe nut on the underside of the attachment piece of the outer cylinder.

At this time, provided that the outer circumferential surface of thecylindrical portion of the caulking nut is corrugated, an extra wallsurrounding the nut attachment hole cuts into the corrugated outercircumferential surface of the cylindrical portion as the nut attachmenthole is diminished in diameter, the extra wall acts as a steady rest torestrain the caulking nut from turning together with the bolt.

When the attachment piece of the outer cylinder and the outer cylinderattachment plate of a vehicle body are curved in the form of a sphericalsurface, the aforementioned means may appropriately be used for a strutmount. Where the form of a spherical surface denotes a curved surfaceconstituting a part of a sphere.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a strut mount of the present invention.

FIG. 2 is a perspective view of a caulking nut of the invention showinga cylindrical portion being diminished in diameter.

FIG. 3 is a sectional view showing the state of attachment of thecaulking nut of FIG.2.

FIG. 4 is a perspective view of a caulking nut showing anotherembodiment.

FIG. 5 is a sectional view showing the state of attachment of thecaulking nut of FIG.4.

FIG. 6 is a sectional view of conventional strut mount.

BEST MODE FOR CARRYING OUT THE INVENTION

Best mode for carrying out the strut mount of the present invention willbe hereinafter described with reference to the drawings. FIG. 1 is asectional view of the strut mount of the invention. FIG. 2 is aperspective view of the caulking nut used for the present embodiment ofthe invention. FIG. 3 is a sectional view of the caulking nut stuck tothe nut attachment hole of the outer cylinder attachment piece.

The strut mount comprises an inner cylinder 1 to which a piston rod of abuffer is fixed, an outer cylinder 2 attached to the vehicle body side,a rubber elastomer 3 in the form of a ring interposed between the innerand outer cylinders 1, 2 to dampen input vibration, the outer cylinder 2being fastened on the outer cylinder attachment plate 6 curved in theform of upwardly convex sphere on the vehicle body side by the bolt 4and the caulking nut 5.

The inner cylinder 1 is a tubular steel product disposed on the insideof the rubber elastomer 3, and at its lower extremity an inwardlyannular flange 7 is formed in the direction square to the axialdirection. Inside of the inner cylinder 1 there is space for fixing thepiston rod that inserts through inside the flange 7 from the undersideby a nut, etc. The inner circumferential surface of the rubber elastomer3 is vulcanization adhered to the outer circumferential surface of theinner cylinder 1. A steel tubular bound bumper seat 8 is disposed on theunderside of the inner cylinder 1, at the upper extremity thereof anannular flange 9 formed inwardly is stacked on the flange 7 of the innercylinder 1, where by the inner cylinder 1 is integral with the boundbumper seat 8.

The outer cylinder 2 is a tubular steel product disposed nearlyconcentrically with the inner cylinder 1 so as to cover the innercylinder 1 from outside and embedded in the rubber elastomer 3. At theupper extremity of the outer cylinder 3, a curved annular attachmentpiece 10 is formed so as to be outwardly in the direction square to theaxial direction and become higher on the inside. The attachment piece 10is tightened on the underside of the outer cylinder attachment plate 6of the vehicle body by the bolt. The portion of the attachment piece 10to be tightened by the bolt, where a nut attachment hole 11 is drilled,is projected outside of the rubber elastomer 3. A caulking nut 5 isstuck to the nut attachment hole 11.

The caulking nut 5 comprises a nut portion 12 disposed on the undersideof the attachment piece 10 and a cylindrical portion 13 inserted intothe nut attachment hole 11 from the underside. On the innercircumferential surface of the nut portion 12 and the cylindricalportion 13, screw threads are cut continuously, wherein the bolt 4 isscrewed. The caulking nut 5 is stuck to the nut attachment hole 11, thecircumference of which, on the attachment piece 10, is pressurized andcaulked, which is then diminished in diameter. For the purpose of makingharder than the attachment piece 10, the caulking nut 5 is a hardenedsteel product.

Having larger diameter than the nut attachment hole 11, the nut portion12 gets caught in the circumferential edge of the nut attachment hole 11so as not to slip through and come out the attachment piece 10 upwardly.A groove 14 is made around the cylindrical portion 13 above the nutportion 12, so extra wall of the attachment piece 10 cuts into therewhen pressurizing the circumference of the nut attachment hole 11.

The cylindrical portion 13 has an outside diameter enough to be insertedinto the nut attachment hole 11, and its outer circumferential surfaceis corrugated so that the extra wall of the attachment piece 10 cutsinto the cylindrical portion 13 when pressurizing the circumference ofthe nut attachment hole 11. The closer to the base extremity side (lowerside) the cylindrical portion 13 reaches, the deeper the corrugation 15on the outer circumferential surface is formed. The extra wall being cutinto is intended to restrain the caulking nut 5 from slipping throughdownward.

Next, the procedure of attaching the strut mount to the outercylindrical attachment plate 6 of a vehicle body is described below.First, the cylindrical portion 13 of the caulking nut 5 is inserted frombelow into the nut attachment hole 11 of the strut mount assembled, andthen the circumference of the nut attachment hole 11 of the attachmentpiece 10 is pressurized and caulked from above.

At this time, the nut attachment hole 11 is diminished in diameter, andthe inner circumferential surface thereof is stuck fast to thecylindrical portion 13. Further, the extra wall of the attachment piece10 cuts into the corrugation 15 on the outer circumferential surface ofthe cylindrical portion 13, whereby forming a steady rest that restrainsthe bolt 4 from turning together with the caulking nut 5, with theresult to secure predetermined turning torque. Being made of hardenedsteel, the caulking nut 5 will not be deformed.

With the strut mount lifted up so that the inner cylinder 1 passesthrough an opening 16 of the outer cylinder attachment plate 6 of thevehicle body, and also with the underside of the bolt hole 17 on theouter cylinder attachment plate 6 of the vehicle body aligned with thebolt hole of the caulking nut 5, the bolt 4 inserted vertically into theplate surface from above the outer cylinder attachment plate 6 through awasher 18 is screwed into the caulking nut 5 and the attachment piece 10of the outer cylinder 2 is bolted to the outer cylinder attachment plate6 of the vehicle body, then attachment of the strut mount is completed.

According to the configuration described above, since the bolt 4 can beinserted perpendicularly to the plate surface even when the outercylinder attachment plate 6 of the vehicle body is curved, it is notnecessary to make the bolt hole 17 of the outer cylinder attachmentplate 6 larger, and problems such as looseness can be dissolved.Further, since the attachment piece 10 is caulked to stick the caulkingnut 5, it is not necessary to thicken the attachment piece 10 of theouter cylinder 2 just like in the case of burring working, so that theweight of the components can be reduced. Besides, because the nut is notwelded, post working can easily be performed even after vulcanizationforming of the rubber, laborsaving during operations.

FIGS. 4 and 5 show other embodiments of the caulking nut. FIG. 4 is aperspective view of the caulking nut when upsetting the cylindricalportion. FIG. 5 is a sectional view of the caulking nut stuck to the nutattachment hole by upsetting the cylindrical portion.

The caulking nut 19 comprises a nut portion 20 disposed on the undersideof the attachment piece 10 and a cylindrical portion 21 that is insertedinto the nut attachment hole 11 from the underside. The caulking nut 19is caulked and secured to the nut attachment hole 11 by pressurizing andupsetting the cylindrical portion 21 outwardly. For the purpose ofmaking harder than the attachment piece 10, the caulking nut 19 is ahardened steel product.

Having larger diameter than the nut attachment hole 11, the nut portion20 gets caught in the circumferential edge of the nut attachment hole 11so as not to slip through and come out of the attachment piece 10upwardly. On the inner circumferential surface of the nut portion 20,screw threads are cut, wherein the bolt 4 is screwed.

The cylindrical portion 21 has an outside diameter enough to be insertedinto the nut attachment hole 11, and its inside diameter is larger thanthat of the nut portion 20 so as not to deform the screw threads of thenut portion 20 when being caulked. Having a chamfering 22 on the aboveside of the circumferential edge of the nut attachmen thole 11, theupsetting upper extremity of the cylindrical portion 21 is gotten caughtso as not to slip through and come out of the caulking nut 19downwardly.

In the configuration described above, when attaching the caulking nut 19to the attachment piece 10, the nut attachment hole 11 is drilled on theattachment piece 10 of the outer cylinder, the cylindrical portion 21integral with the nut portion 20 is provided for the caulking nut 19,and then the cylindrical portion 21 is inserted into the nut attachmenthole 11 from the underside of the outer cylinder attachment piece 10.After that, when the cylindrical portion 21 is upset and then is caulkedand secured to the nut attachment hole 11, the outer circumferentialsurface of the cylindrical portion 21 is stuck fast to the innercircumferential surface of the nut attachment hole 11, whereby the, nut19 can be stuck to the underside of the outer cylinder attachment piece10.

Industrial Applicability

According to the present invention, it will be obvious from thedescription above that rigidity can be raised to improve runningproperties, because the outer cylinder attachment plate can be curved bythe use of the caulking nut stuck to the underside of the attachmentpiece of the outer cylinder, without enlarging the bolt hole of theouter cylinder attachment plate of the vehicle body.

Furthermore, cost reduction can be accomplished by thinning the platethickness to lightweight the products and also labor saving duringoperations. Accordingly, it is an object of the invention to provide anoptimum strut mount as a suspension system for automobile and the like.

What is claimed is:
 1. A mounting assembly for attaching a strut to anouter cylinder attachment plate of a vehicle body, said mountingassembly comprising: an outer cylinder including an attachment piecehaving a hole provided therein; a caulking nut comprising a cylindricalportion, a nut portion and a bolt hole disposed through said cylindricalportion and said nut portion; and a bolt extending through said hole andsaid bolt hole such that a head of said bolt is disposed adjacent to theouter cylinder attachment plate, wherein said cylindrical portion has aplurality of corrugations thereon, wherein said cylindrical portion isdisposed in the hole such that material of said outer cylinder occupiessaid plurality of corrugations thereby inhibiting a rotational movementof said caulking nut.
 2. The mounting assembly as set forth in claim 1,wherein said attachment piece of said outer cylinder is curved in theform of a spherical surface to facilitate attachment to an outercylinder attachment plate that is curved in the form of a sphericalsurface.
 3. The mounting assembly as set forth in claim 1, wherein saidcaulking nut is operable to be caulked and secured to said attachmentpiece of said outer cylinder by pressurizing the circumference of thehole of said attachment piece from a direction normal to said attachmentpiece to decrease the diameter of the hole.
 4. The mounting assembly asset forth in claim 3, wherein said attachment piece of said outercylinder is curved in the form of a spherical surface to facilitateattachment to an outer cylinder attachment plate that is curved in theform of a spherical surface.